Climate Change Pushing Some Fish to Cooler Waters

Climate change seems to be pushing several species of fish and crustaceans northward along the east and west coasts of North America which could have serious effects on birds, marine mammals and those who depend on fishing for food and income.

Photo: NOAA

The black sea bass is among many marine species shifting its range northward to cooler waters as the water in its traditional range warms up.

“As temperatures have warmed in the waters off our coasts, animals with a low tolerance for that warming have just picked up and shifted,” says Malin Pinsky, a marine biologist at Rutgers who is leading a team researching these shifts. “I hesitate to say ‘moved,’ mainly because we don’t yet know whether fish are actually swimming, or whether they’re simply reproducing more slowly in their old ranges and faster in their new ranges.”

Pinsky says lobsters that were once abundant off Long Island have moved to cooler waters of Maine while summer flounder and black sea bass, once common to the waters off Cape Hatteras, have moved north and are now more abundant off the coast of New Jersey.

During the past 18 months, Pinsky, an assistant professor of ecology and evolution in the School of Environmental and Biological Sciences, has published two papers -- Climatic Change in October 2012 and Science in September 2013 -- documenting this trend and exploring its implications. He and his team have found that the shift northward is happening at different rates among the species not because of their biological differences but due to the rate and direction of climate change in their waters.

The data behind this research is now available at a new website, OceanAdapt, built by Pinsky and his colleagues and funded by the U.S. National Marine Fisheries Service.

Much of the information on the website helps to explain how the ecology, business and economics of sport and commercial fishing are connected to the effects of climate change and how difficult it is to adapt to the resulting changes. The challenge now, says Pinsky, who will publish a study in Oceanography this month, is for fisheries, which provide a source of protein to 60 percent of the world’s population, to adapt to these changes.

Photo: Shonda Foster

Malin Pinsky, assistant professor of ecology and evolution, School of Environmental and Biological Sciences.

In the case of the black sea bass, for instance, the Atlantic States Marine Fisheries Commission, which regulates certain fisheries in the eastern United States, still allocates quotas among states according to their distribution in the late 1980s and early 1990s. At that time, black sea bass was more often caught in Virginia than in New York, while the bass is now found further north.

The regulations require that fish caught in North Carolina, for instance, be distributed and sold from North Carolina. While the number of black bass that can be harvested in North Carolina is the same as it was two decades ago, the black bass population has dwindled in those waters -- forcing fishermen from North Carolina to travel to New Jersey to do their harvesting.

Pinsky says there needs to be fundamental changes made for fisheries to remain healthy as changes in climate continue to affect the stability of marine life.

While a number of species like the black sea bass are shifting their habitat range, not all species are moving at the same rate, Pinsky says. Although it isn’t clear how this separation of predators will affect the food web in the future, it may force birds and mammals that rely on fish to survive, to find new food and prey elsewhere.

“We don’t necessarily foresee a catastrophic collapse,” says Pinsky. “Species that are heavily overfished are especially sensitive to climate change, and so allowing overfished species to recover may be one of the best things we can do for preserving fisheries in the future.”